Hardfacing alloys are used to impart wear-resistance to less expensive alloys in a variety of industries and applications. Cobalt is a key constitutent of the best performing of the hardfacing alloys that are most extensively used. Because of the high cost of cobalt and because its market price fluctuates significantly, there is a need to develop hardfacing alloys with reduced levels of cobalt. A special need exists to reduce the cobalt content of the hardfacing alloys used in the primary system of nuclear power plants. The small amount of wear and corrosion the cobalt-base alloys experience ultimately results in the formation of the gamma-emitting isotope .sup.60 Co. This isotope is incorporated into the oxides that form on out-of-core component that must be inspected, repaired or replaced by maintenance personnel. The activated .sup.60 Co is responsible for most of the radiation exposure these workers receive.
However, a cobalt-free or low-cobalt hardfacing alloy must, in addition to being wear-resistant, also show adequate levels of hardness, weldability and corrosion resistance. It would therefore be desirable to utilize cobalt-free hardfacing alloys which have adequate or improved wear resistance, galling resistance, hardness and mechanical properties in diverse applications.
It is thus an object of the present invention to provide novel wear-resistant, anti-galling, cobalt-free hardfacing alloys.
It is yet another object of the present invention to provide methods for constructing components exposed to wear and corrosive (aggressive) environments, whereby the components are hardfaced with wear-resistant, anti-galling, cobalt-free alloys.
These and other objects of the invention will be made apparent from the following description of the preferred embodiments and appended claims.